CC BY
11
УДК 81'33
Р. К. Потапова, А. В. Джунковский
Потапова Р. К., доктор филологических наук, профессор; действительный член Международной академии информатизации; заведующая кафедрой прикладной и экспериментальной лингвистики; директор Института прикладной и математической лингвистики МГЛУ; e-maiL: rkpotapova@yandex.ru
Джунковский А. В., аспирант; специалист по учебно-методической работе кафедры прикладной и экспериментальной лингвистики Института прикладной и математической лингвистики МГЛУ; e-maiL: Vetinari01@gmaiL.com
ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ СТЕГАНОГРАФИЧЕСКИХ ТЕХНОЛОГИЙ В ЗВУЧАЩЕЙ РЕЧИ НА СОВРЕМЕННОМ ЭТАПЕ РАЗВИТИЯ1
В статье рассматриваются современные достижения в области применения стеганографических технологий в звучащей речи. Актуальность статьи связана с необходимостью разработки научно-обусловленного подхода в вопросе использования стеганографических и стеганоаналитических технологий, а также их разработки. В настоящее время существует некоторое количество работ по стега-ноанализу звучащей речи, а также ведется разработка соответствующего подхода для письменных текстов русского языка. Тем не менее общий уровень развития стеганографии как науки требует серьезного рассмотрения. В этих условиях мы рассматриваем главные достижения отечественных и зарубежных ученых в данной области. В современном мире область применения классических криптографических технологий становится узкой, в связи с чем анализ стеганографических технологий имеет большое практическое значение.
Ключевые слова: стеганография; стеганоанализ; контейнер; восприятие человеком; методология стеганоанализа; звучащая речь.
R. K. Potapova, A. V. Dzhunkovskiy
Potapova R. K., Sc. D., Prof., FuLL Member of the international Informatization Academy, Head of Department of AppLied and Experimental Linguistics, Director of institute of AppLied and Mathematical Linguistics of Moscow State Linguistic University (MSLU); e-maiL: rkpotapova@yandex.ru Dzhunkovskiy A. V., Postgraduate Student, MethodoLogy and Education SpeciaList of the Department of AppLied and ExperimentaL Linguistics, institute of AppLied and MathematicaL Linguistics of Moscow State Linguistic University (MSLU); e-maiL: Vetinari01@gmaiL.com
1 The research is supported by the Russian Science Foundation (project № 18-1800477).
Р. К. Потапова, А. В. Джунковский
PROSPECTS OF USING MODERN STEGANOGRAPHIC SPOKEN LANGUAGE TECHNOLOGIES
In this paper, we present our findings concerning modern achievements in the field of steganographic technologies in spoken language. The article deals with the modern state of affairs in the field of steganography and steganalysis: a scientific approach to these fields is only being developed. Such an approach is prerequisite for developing steganographic technologies. Currently there exists a number of studies that cover the use of steganography in spoken language. There is also a number of studies that consider the prospects and the efficiency of using steganography in written texts. However, the overall level of development in this field remains somewhat lacking. We aim to consider the main achievements of both Russian and foreign scientists in this field. The usage of cryptography in the modern world is becoming limited which makes the creation of a holistic scientific approach to steganography an issues of high practical importance.
Key words: steganography; steganalysis; container; cipher; human perception; steganalysis methodology; spoken language.
I. Introduction
In the modern world, the advent of computational technologies has quickly altered the landscape of available information protection technologies as well as simultaneously increasing the demand for such methods.
Contemporarily, cryptography is still relevant while encrypting information automatically and in large volumes. However, the usage of cryptography in applications that require higher levels of protection, prolonged periods of confidentiality and lower costs is suboptimal. Furthermore, cryptographic methods contain an inherent issue: the fact of concealing information is either evident to the naked eye or is perceived as highly likely. For some applications, this is unacceptable as the very fact of concealing information may be counterproductive to the privacy efforts.
The very nature of cryptography dictates that encryption must follow strict, if often obscure and unintuitive, mathematical patterns. Thus, both encryption and decryption of information by crypto-means is nowadays a question of computational power and algorithmization. [Потапова 2010, p. 120].
The significance of steganography and steganalysis lies in the fact that these methods are by their very nature highly protected from automatic and computer-aided counteraction technologies [Лукьянов 2005, p. 7].
Successful creation and breaching of steganological technologies requires a highly skilled human expert [Алферов, Зубов 2012, p. 67].
The entire field of linguistic steganography is rather underdeveloped as ofnow [Bennet 2013, p. 15]. One notable problem when considering issues in this field is the fact that steganographic methods differ in application and efficiency in different languages. Studies do not yield universal results: each language needs to be studies separately. Some papers cover the methodology of steganalysis and steganography in written Russian texts [Dzhunkovskiy 2018, p. 119], while other notable works deal with the issue of steganography in other languages [Wayner 2002, p. 78].
II. Methods
The nature of our research is analytical. Hence, the tools employed are of a similar nature. The analysis and synthesis of the scarce contemporary data available from the works of experts in steganography and steganalysis working with various languages provides limited basis for our research [Xiang, Sun, Luo 2014, p. 1894]. However, additional theoretical framework [Katzenbeisser 2000, p. 87] [Wayner 2005, p. 163] enhances these analytical efforts.
When it comes to steganography when applied to the Russian language, there is a small selection of works that deal with written texts [Dzhunkovskiy 2018] and spoken language [Пономарь 2010].
III. Results
When it comes to text linguistic steganography, a classification of methods exists. The tri-stage steganalytical method allows the human expert to determine the likelihood of steganographical alterations in the text.
The first step is the meta-analytical step during which the format and design elements of the text are examined. Step two presupposes the main linguistic analysis. Finally, step three is the extralinguistic analysis, during which the contents of the message are checked against objective reality [Dzhunkovskiy 2018].
These methods do not carry over to steganalytical efforts when working with spoken language. At the same time, another set of unique methods exists. These methods deal with altering the prosodic speech characteristics, such as the base tone frequency, intensity, fragment length and others [Пономарь 2010].
P. K. nomanoBa, A. B. flrnyHKOBCKUu
The proposed method is described as being robust to rediscretization, vocoder modifications, lossy compression and noises. The method itself presupposes altering audio signals with audio file editing tools. The results have demonstrated that from the psychoacoustics point of view, a 5 % alteration of the main tone frequency was undetectable to 98.9 %% of human subjects.
This research shows that prosodic attributes of spoken language can be used as effective steganographic containers. However, their efficiency is only present when the attackers rely solely on human auditory perception with no additional computer analysis tools.
IV. Discussion
The situation with steganography applications in the Russian language is rather interesting. Methods applicable to written texts are in both theory and practice highly robust against computer semi-automatic and automatic steganalytical method, whereas methods used to alter sound files with stego provide high levels of protection against human experts.
It is important to note that there is indeed a high level of application to audiolinguistic steganography based on altering the prosodic features of the signal (F0 - fundamental frequency, In - intensity, Tn - duration). However, the implementation of these alterations requires a high level of technical expertise.
It would not be in error to state that the audio-linguistic steganography methods fully adhere to some of the main principles of steganography as a whole: the very act of detecting the aforementioned alterations is highly complex. However, this can be theoretically accomplished with an unacceptably high detection rate when using computer analysis tools. These considerations demonstrate the need to conduct additional analysis to determine the rate at which audio-linguistic alterations of the prosodic features of audio signal can be detected with the use of computer-assisted and semi-automated analysis tools.
The authors of the method under analysis posit that the detection rates of the considered alterations would also depend on whether cryptographic methods are used as a second-stage security measure after employing steganographic methods. This idea has theoretical potential, but poses a new issue of the different variables involved when considering the efficiency of steganographic methods in conjunction with cryptographic ones.
V. Conclusions
Steganographic and steganalytical methods for Russian written and audio texts are being rapidly developed in modern science. Previously, steganography has remained an art as opposed to a science. This state of affairs is now changing.
The modern methods of steganography in spoken Russian language rely on digitally altering prosodic characteristics of the audio feed. This method provides high levels of protection against human auditory perception, however its robustness against automatic, semi-automatic and computer-assisted analysis remains a concern, therefore requiring additional inquiry into this subject matter.
СПИСОК ЛИТЕРАТУРЫ
Алферов А. П., Зубов А. Ю. и др. Основы криптографии. М. : Гелиос АРВ, 2012. 480 с.
Лукьянов Г. В. Основы кодирования и криптографического преобразования
информации. М. : ООО Сарма, 2005. 128 с. Пономарь М. О. Использование вариативности речевой просодии при создании интеллектуальных систем защиты информации // Вестник Московского государственного университета. 2010. Вып. 580. С. 265-271. Потапова Р. К. Речь: коммуникация, информация, кибернетика. М. : Изд-во УРСС, 2010. 600 с.
Bennet K. Linguistic Steganography: Survey, Analysis, and Robustness Concerns
for Hiding Information in Text // CERIAS Tech Report. 2013. № 4. P. 1-30. Dzhunkovskiy A. V. Steganography: Three-Stage Analysis Methodology Applied to Russian Written Texts // Вестник Московского государственного лингвистического университета. Гуманитарные науки. 2018. Вып. 6 (797). С. 117-123.
Encyclopedia of Cryptography and Security / van Tilborg H. C. A., Jajodia S. 2nd
ed. Berlin : Springer Science & Business Media, 2014. 1416 p. Katzenbeisser S. Principles of Steganography. Boston : Artech House, 2000. 186 p.
Wayner P. Disappearing Cryptography: Information Hiding. San Francisco : Morgan Kaufmann, 2002. 221 p. Wayner P. Strong Theoretical Steganography. Berlin : Cryptologia, 2005. 410 p. Xiang L. Sun X., Luo G. Linguistic Steganalysis Using the Features Derived from Synonym Frequency // Multimedia Tools and Applications. 2014. № 3. P. 1893-1911.
Р. К. Потапова, А. В. Джунковский
REFERENCES
Alferov A. P., Zubov A. Ju. i dr. Osnovy kriptografii. M. : Gelios ARV, 2012. 480 s.
Luk'janov G. V. Osnovy kodirovanija i kriptograficheskogo preobrazovanija infor-macii. M. : OOO Sarma, 2005. 128 s.
Ponomar' M. O. Ispol'zovanie variativnosti rechevoj prosodii pri sozdanii intellektual'nyh sistem zashhity informacii // Vestnik Moskovskogo go-sudarstvennogo universiteta. 2010. Vyp. 580. S. 265-271.
Potapova R. K. Rech': kommunikacija, informacija, kibernetika. M. : Izd-vo URSS, 2010. 600 s.
Bennet K. Linguistic Steganography: Survey, Analysis, and Robustness Concerns for Hiding Information in Text // CERIAS Tech Report. 2013. № 4. P. 1-30.
Dzhunkovskiy A. V. Steganography: Three-Stage Analysis Methodology Applied to Russian Written Texts // Вестник Московского государственного лингвистического университета. Гуманитарные науки. 2018. Вып. 6 (797). С. 117-123.
Encyclopedia of Cryptography and Security / van Tilborg H.C.A., Jajodia S. Second Edition. Berlin : Springer Science & Business Media, 2014. 1416 p.
Katzenbeisser S. Principles of Steganography. Boston : Artech House, 2000. 186 p.
Wayner P. Disappearing Cryptography: Information Hiding. San Francisco : Morgan Kaufmann, 2002. 221 p.
Wayner P. Strong Theoretical Steganography. Berlin : Cryptologia, 2005. 410 p.
Xiang L. Sun X., Luo G. Linguistic Steganalysis Using the Features Derived from Synonym Frequency // Multimedia Tools and Applications. 2014. № 3. P. 1893-1911.
